Seed tape including successively arranged germinating units as well as a method of germinating said tape

ABSTRACT

A seed tape including successively arranged germinating units ( 1   a,    1   b,    1   c ) is made of at least one carrier strip ( 2 ) as well as at least one layer ( 3 ) of biodegradable, gas-permeable material placed on said carrier strip. Each germinating unit ( 1   a,    1   b,    1   c ) includes a mixture of carrier ( 7 ), at least one additive ( 8 ) and optionally an adjuvant(s) ( 9 ) in addition to one or more seeds ( 10 ). The layer ( 3 ) of biodegradable, gas-permeable material is flexible and non-woven. The additive or additives ( 8 ) are water-absorbing. In this manner the seed tape is particularly suited for being subjected to a pregermination procedure because it possesses a very high capacity of retaining water without disintegrating.

TECHNICAL FIELD

The invention relates to a seed tape as stated in the preamble of claim1.

In this description the expression “carrier” should be understood so asto cover a material including at least one of the substances:granulated, expanded vermiculite, perlite, zeolite, cellulose materials,such as wood fibres and sphagnum burned clay, rock wool or the likesubstances.

Further the expression “adjuvant” should be understood so as to coverone or more substances selected among plant nutrients, plantprotectants, such as pesticides, including herbicides, insecticides,especially systemic insecticides, fungicides, virae, cultures ofbacteria, cultures of fungi, such as Trichoderma, fungus spores,microencapsulated fungicides, eggs from useful insects, such aspredatory nematodes, fertilizers, enzymes, animal repellants, hormones,pH-adjusting agents, carbon, clay particles, trace elements, such asmolybdenum, wood fibres or wood powder, kieselguhr, surfactants or othersubstances with a favourable effect on the germination and the growth ofplants, where several substances are available in microencapsulatedform.

By the expression “biodegradable material” is ment a material graduallydisintegrating when left alone in its natural state so as to be part ofthe ordinary biological circuit.

BACKGROUND ART

One of the most vital conditions for a seed to start germinating is thatthe enzymes and hormones present in the seed coat are brought intocontact with the germ and the white of the seed. This is supported bymeans of water. When a high number of seeds are moistened with water,the water with the dissolved enzymes and hormones reaches the white andthe germ of the individual seeds at a time varying from seed to seed.Accordingly, these seeds start to germinate at various times. Such adeveloping period is not completely satisfying as nothing but aninsignificant time delay with respect to the development of theindividual germinating periods implies that the seeds develop intoplants which at the harvesting present a rather significant differencein weight. The latter is very disadvantageous for the farmer who wantsall plants to be equally developed at the harvesting in such a mannerthat he or she obtains the best possible yield on the field with theseeds sowed therein. In view of the above a demand applies for the seedsto be subjected to a pregermination procedure whereby additional wateris fed in such a manner that all the seeds have developed equally withrespect to germination when they are bedded out in the ground.

It is known to pellet seeds in order to provide the seeds withadditional nutrition and protection. Frequently, the seed pill includesone or more layers of clay, and it is impossible to incorporate thewater reserves necessary for the pregermination into such pills becausethe clay coat encircling the seeds disintegrates in connection with thefeeding thereto of water.

From the International publication No WO 01/56361 A1 a seed tape isknown including successively arranged germinating units. Said tapeincludes at least one carrier strip as well as at least one layer ofbiodegradable, gas-permeable material arranged on said carrier strip.Each germinating unit includes a mixture of carrier and at least oneadditive in addition to one or more seeds; the layer of biodegradable,gas-permeable material is flexible and non-woven. Said addition oradditives is/are water absorbing.

BRIEF DESCRIPTION OF THE INVENTION

The object of the invention is to provide a seed tape of the above typewhich is suited for being subjected to a germination procedure asdescribed above, and which at the pregermination procedure isparticularly capable of retaining water without disintegrating.

The seed tape according to the invention is characterised in that thelayer of biodegradable, gas-permeable material, which is flexible andnon-woven, is made of polylactide (PLA) or a material includingpolylactide, or is made of rayon, viscose or polylactide plus starch. Asa result, the germinating units are particularly capable of retainingthe water amounts necessary for an optimum pregermination procedure. Thelatter is due to the fact that the materials of the germinating unitsencircling the seeds can act as a kind of “cocoons” which on the innerside can maintain an optimum moist microclimate around each seed afterthe watering. This microclimate can compensate for the air or the groundaround or at a short distance from the seed tape optionally being lessmoist during a period. In other words, each “cocoon” provides a moisturebuffer function. Even in the moist, viz. swollen, and optionally wateredstate, the germinating units tolerate considerable stress effects, suchas in connection with a maximum bedding out without said germinatingunits breaking or being weakened and even though radicles or seed leavesshould penetrate said germinating units. The flexible non-woven layer isparticularly suited for carrying seeds, carrier and adjuvant. Thecarrier assists in preventing the necessary amount of air from beingdriven out of each “cocoon” in case of a prolonged uncontrolled supplyof water from the surroundings. The biodegradability is very high aswell.

The water-absorbing material may be cotton, preferably of a fibrediameter of 19 to 21 μm with the result that a long-term moistmicroclimate is obtained around each seed in an excellent manner, saidclimate enhancing the pregermination.

In addition, the PLA-fibres may according to the invention present aslightly creased structure.

Furthermore, the carrier strip may according to the invention be made ofPLA, such as non-woven PLA.

According to the invention super absorbing polymer (SAP) grains orfibres may be arranged around and adjacent the seed, said SAP-grains orfibres being retained by means of an adhesive effect resulting from anultrasound or heat treatment of the non-woven material. In this mannerthe seed tape is particularly resistant to disadvantageous stresseffects from the outside.

In addition, the non-woven PLA-material may according to the inventionpresent a needle structure and be structured as a sandwich with threecrossed layers, where the middle layer includes relatively thin fibresand the two outer layers include fibres being somewhat thicker than thefibres of the middle layer. The resulting non-woven, PLA-layer canpresent a suitable gas-permeability.

According to the invention, the SAP-grains or fibres may be retainedadjacent the seed by being glued onto the non-woven material by means ofadditional glue; preferably biodegradable natural glue, such as astarch, gelatine or sugar-based glue with the result that the grains orfibres are exceptionally well fastened to the non-woven material.

Furthermore, each germinating unit may according to the invention bedelimited by two spaced transverse line weldings, whereby at least tworelatively short auxiliary weldings maybe provided between these lineweldings, said auxiliary weldings projecting inwards from each side edgeof the seed tape and having a length of 0.05 to 0.20 times the width ofthe seed tape. As a result, the seed or seeds as well as the mixture ofcarrier, water-absorbing additive and optionally adjuvant are reliablyretained in position inside the “cocoon”. In addition, germ leaves andradicles can easily find a way into the ground, viz. between theauxiliary weldings.

According to the invention, the spot or line weldings may be provided ata temperature of 70 to 110° C. As a result, a suitable adhesiveness isobtained between the PLA and the paper, the seed and the water-absorbingadditive, respectively.

According to the invention, the fibres of each non-woven layer may be ofa length of 5 to 9 cm. These fibre proportions turned out to beparticularly advantageous.

Moreover, the biodegradable, gas-permeable, flexible non-woven layer mayaccording to the invention be formed by a row of pockets of non-wovenpolylactide (PLA) fastened to the carrier strip at an equidistantdistance, and where each pocket includes a seed; this turned out to beparticularly advantageous as well.

According to the invention the flexible woven PLA layer may preferablyhave a weight of 10 to 40 g/m².

Moreover, when the seeds are preferably sugar beet seeds, eachgerminating unit may according to the invention be delimited by acircumferential welded seam, which is locally interrupted in order toprovide openings allowing radicles and seedlings to penetratetherethrough. This embodiment is particularly suited in connection withan accurate seeding.

Also, according to the invention, compressed small pieces may beproduced by placing paper pulp, optionally cellulose fibres,SAP-crystals and grains of carrier and adjuvants, for instance on thesurface of a suction cylinder by means of air. This provides a simpleproduction of said pieces.

Moreover, adjuvants, such as pesticides, may according to the inventionbe available in a small capsule in each germinating unit, whereby aparticularly easy administration of the pesticide is obtained.

According to the invention, the flexible non-woven PLA-layer mayadvantageously present a suction capacity of 0 to 30 mm, for instance 5to 15 mm with the result that the PLA-layer can present a suitable wickeffect.

According to the invention, the water-absorbing additive or additives,such as SAP and optionally adjuvants, such as pesticides, may beabsorbed in or adhered to a blotting paper piece optionally providedwith a plastic coating, such as a PLA coating, for a slow release of theadditive and/or the adjuvant, said blotting paper piece being placedinside each germinating unit and for instance resulting from a cuttingoff from a high speed produced roll of blotting paper, such as at 500m/min, where the above water-absorbing additive and adjuvant, if any,are sucked into or glued onto said blotting paper piece. In this mannerthe additive and the adjuvant, if any, can be administered in a verysimple manner in each germinating unit because no more than one pieceneed be inserted in each germinating unit. These pieces are alsocost-effective due to a very rational manufacture.

BRIEF DESCRIPTION OF THE DRAWING

The invention is explained in detail below with reference to thedrawing, in which

FIG. 1 is a perspective view of an embodiment of the seed tape accordingto the invention,

FIG. 2 is a perspective view of a portion of a second embodiment of theseed tape,

FIG. 3 is a front view of a portion of a third embodiment of the seedtape,

FIG. 4 is a cross sectional view of an embodiment of the seed tapeincluding separating layers,

FIG. 5 is a front view of a portion of a fourth embodiment of the seedtape,

FIG. 6 is a perspective view of a piece according to the invention,

FIG. 7 is a perspective view of a capsule according to the invention,

FIG. 8 is a perspective view of a piece according to the inventionstructured as a sandwich, and

FIG. 9 is a perspective view of a blotting paper piece according to theinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

The seed tape of FIG. 1 includes many successively arranged germinatingunits, only three germinating units 1 a, 1 b og 1 c being shown. Theseed tape includes at least a biodegradable carrier strip 2 as well asat least one layer 3 of biodegradable gas-permeable material arranged onsaid strip. An additional carrier strip is indicated at 4. The layer 3can be locally interrupted over a short distance along the seed tape,which, however, has not been illustrated. Each germinating unit 1 a, 1b, 1 c includes a mixture of carrier 7 and at least one water-absorbingadditive 8 in addition to one or more seeds 10. One or more adjuvants 9can also be present. Each carrier 7 and each adjuvant 9 includes atleast one of the substances described above.

The water-absorbing additive or additives 8 can for instance be cotton,preferably a cotton of a fibre diameter of 19 to 21μ.

The layer 3 of biodegradable, gas-permeable material is flexible andnon-woven. It can be hot-adhesive and for instance be made ofpolylactide (PLA) or a material containing said PLA or be made of rayon,viscose or polylactide plus starch. The layer 3 can be a non-wovenmaterial made of PLA-fibres with a slightly creased structure. Thecarrier strip 2 can be made of paper and preferably be of a weight of 14to 60 g/m², preferably 22 g/m². However, the carrier strip can also bemade of PLA, such as non-woven PLA.

The water-absorbing additive or additives 8 can be superabsorbingpolymers (SAP) present in form of grains or fibres of an average weightof 0.05 to 0.42 mg/grain or fibre. In FIG. 1, these SAP-grains 8 havebeen illustrated in an exaggerated size for the sake of clarity of theFigure. The SAP-grains can for instance be cross-linked polyacrylic acidsalts, cross-linked isobutylene-maleic acid-copolymer derivatives, saltsof cross-linked starch-polyacrylic acid, salts of cross-linkedpolyvinyl-alcohol-polyacrylic acid, cross-linked polyvinylalcoholderivatives, cross-linkedpoly-ethylene-glycol derivatives andcross-linked carboxymethylcellulose derivatives.

The SAP-grains or fibres 8 can be of an average weight of 0.18 to 0.36mg/grain or fibre, preferably approximately 0.27 mg/grain or fibre. Itis also possible that the SAP-grains or fibres 8 are of an average size,viz. “diameter”, of between 450 and 750μ, preferably between 550 and650μ, especially approximately 600μ.

The SAP-grains or fibres 8 can be arranged around and adjacent the seed10, said SAP-grains or fibres being retained by means of an adhesiveeffect resulting from an ultrasound or heat treatment of the PLAmaterial.

The non-woven PLA-material 3 can present a needle structure andpreferably be structured as a sandwich not shown with three crossedPLA-fibre layers, where the middle layer includes relatively thin fibresand the two outer layers include fibres being somewhat thicker than thefibres of the middle layer. The fibres of each layer are arbitrarilyarranged relative to one another.

The SAP-grains or fibres 8 can be retained adjacent the seed by beingglued onto the non-woven material 3 by means of additional glue.However, this glue does not appear from the Figure.

The glue can be a biodegradable natural glue, such as a starch, gelatineor sugar-based glue.

In FIG. 1, the strip 2 can for instance be kraft paper, whereas thelayer 3 can be made of non-woven PLA as mentioned above, and a paperlayer 4 can be placed on said layer 3. The layers can be fastened to oneanother by way of spot or line welding, optionally in combination with alocal compression of the kraft paper and the PLA-layer.

As shown in FIG. 3, each germinating unit can be delimited by two spacedtransverse spot or line weldings 16, and at least two relatively shortauxiliary weldings 17 can be provided between said spot or lineweldings. These auxiliary weldings 17 project inwards from each sideedge 18 of the seed tape and are of a length a of 0.05 to 0.20,preferably 0.1 to 0.15, especially 0.12 times the width b of the seedtape.

When the flexible non-woven layer 3 is made of PLA, the spot or lineweldings 16 can be provided at a temperature of 70 to 110° C.

The fibres of the non-woven layer 3 can be of a length of 5 to 9 cm,preferably 6 to 8 cm, and a thickness of 0.1 to 0.2 mm.

The water-absorbing material 8 can be made of silica particles insteadof the above SAP-grains or fibres.

As shown in FIG. 2, the seed tape can include a carrier strip 2′, andthe biodegradable, gas-permeable non-woven layer can be fastened to saidcarrier strip in form of a row of pockets 3′ of non-woven polylactide(PLA), said pockets preferably being arranged at an equidistantdistance.

The flexible non-woven PLA-layer 3 can have a weight of 10 to 40 g/m²,preferably 14 to 25 g/m², especially 22 g/m². The paper strip 2 caninclude fibres of PLA, preferably of a fibre length of 4 to 7 mm.

As shown in FIG. 4, at least one thin separating layer 20 ofbiodegradable film can be placed in parallel to the biodegradableflexible non-woven layer 3, said thin separating layer optionally beinga semi-permeable film, preferably of PLA, gelatine or cellulose(cellophane®) and preferably of a thickness of 20 to 75 μm, especially30 to 50 μm. Thus the separating layers 20 separate the carrier, theadjuvant and the water-absorbing additive. As the separating layers aregradually disintegrated, the above materials are released.

When the seeds are sugar beet seeds, each germinating unit can bedelimited by a circumferential welded seam 26, cf. FIG. 5, which isoptionally locally interrupted in order to provide openings 27 allowingradicles and seedlings to penetrate from each seed.

As shown in FIG. 6, the mixture of carrier 7, water-absorbing additive 8and optionally adjuvant 9 can be compressed into a small piece 21 which,if desired, can also include the seed or the seeds 10.

The pieces 21 a (FIG. 3) or 27 a (FIG. 9) can be provided by placingpaper pulp, SAP-crystals and grains of carrier 7 and adjuvant 9 by meansof air on for instance the prepunched surface of a suction cylinder notshown.

The adjuvant 9, such as pesticides, can, if desired, be placed in asmall closed capsule 22, cf. FIG. 7, inserted in each germinating unitin order to allow a “slow release” of said pesticides.

In addition, said piece can be constituted by a sandwich 23, cf FIG. 8,which is delimited by layers 25 a, 25 b of non-woven PLA on the outsideand which on the inside contains the carrier 7, the adjuvant 9 and thewater-absorbing additive 8 optionally in connection with the separatinglayers 29, said piece for instance being dimensioned substantially as astamp.

The flexible non-woven PLA-layer 3 in the germinating unit 1 a, 1 b, 1 ccan present a suction capacity of 0 to 30 mm, for instance 5 to 15 mm,estimated according to the method indicated in H. J. Hannover and SigurdSmith: Papirfabrikation (“Production of Paper”) Julius Gjellerups Forlag1934, page 277. The suction capacity is the height measured in mm towhich said layer 3 can suck the water in 10 min, the layer 3 beingpresent as a vertically suspended strip of the layer 3.

Furthermore it is possible that the water-absorbing additive oradditives 8, such as SAP, and optionally adjuvants 9, such aspesticides, can be absorbed in or adhered to a blotting paper piece 27 aoptionally provided with a plastic coating, such as a PLA-coating, for a“slow release” of additive 8 and/or adjuvant 9. This blotting paperpiece 27 a can be placed inside each germinating unit 1 a, 1 b, 1 c, cf.FIG. 3, and for instance result from a cutting off from a high speedproduced roll of blotting paper, such as at 500 m/min, where the abovewater-absorbing additive and adjuvant, if any, is sucked into or gluedonto said blotting paper.

The invention maybe modified in many ways without thereby deviating fromthe scope of the invention, as it appears from the attached claims.Thus, the strip 4 in the seed tape 1 can be replaced by a coating, whichis placed for instance on top of the non-woven layer 3, whereby the seed10, the carrier 7, the adjuvant 9 and the additive 8 are then retainedagainst the layer 3 by said coating. The latter option is, however, notshown.

It should be noted that the seed tape according to the invention hasnothing to do with covering materials or strips containing seeds andadjuvants, and which are intended to be placed on the bare surface ofthe ground, especially in areas suffering from difficult growthconditions. As far as the seed tape according to the invention orportions thereof is concerned the seed tape or seed tapes are placedeither horizontally or vertically at a suitable depth below the surfaceof the ground.

The flexible non-woven layer 3 of biodegradable, gas-permeable materialcan also be a polymer, for instance a polyester or another oil-basedpolymer; it can optionally be an aliphatic-aromatic polycondensationcopolymer derived from dipidic terephtalic acid and butanediol.

1. A seed tape (1) including successively arranged germinating units (1a, 1 b, 1 c), and which further includes at least one carrier strip(2,4) as well as at least one layer (3) of biodegradable, gas-permeablematerial which is flexible and non-woven and arranged on said carrierstrip, whereby each germinating unit (1 a, 1 b, 1 c) includes a mixtureof carrier (7), at least one additive (8) which is water-absorbing andone or more seeds (10), characterised in that the layer (3) ofbiodegradable, gas-permeable material which is flexible and non-woven,and is made of polylactide (PLA) or a material including saidpolylactide, or is made of rayon, viscose or polylactide plus starch. 2.A seed tape as claimed in claim 1, characterised in that the PLA-fibrespresent a slightly creased structure.
 3. A seed tape as claimed in claim1, characterised in that super absorbing polymer (SAP) grains or SAPfibres (8) are arranged around and adjacent the seed (10), said SAPgrains or SAP fibres being retained by means of an adhesive effectresulting from an ultrasound or heat treatment of the non-wovenmaterial.
 4. A seed tape as claimed in claim 1, characterised in thatthe carrier strip (2, 4) is made of PLA.
 5. A seed tape as claimed inclaim 1, characterised in that the non-woven PLA material (3) presents aneedle structure and is structured as a 10 sandwich with three crossedlayers, where the middle layer includes relatively thin fibres and thetwo outer layers include fibres being thicker than the fibres of themiddle layer.
 6. A seed tape as claimed in claim 3, in which the SAPgrains or SAP fibres (8) are retained adjacent the seed (10),characterised in that said grains or fibres are 15 retained by beingglued onto the non-woven layer (3) by means of biodegradable naturalglue, such as a starch, gelatine or sugar-based glue.
 7. A seed tape asclaimed in claim 1, characterised in that each germinating unit (1 a, 1b, 1 c) is delimited by two spaced transverse spot or I line weldings(16), and that at least two relatively short auxiliary weldings (17) areprovided between the spot or line weldings (16), said auxiliary weldingsprojecting 5 inwards from the side edges (18) of each seed tape andbeing of a length (a); of 0.05 to 0.20 times the width (b) of the seedtape.
 8. A seed tape as claimed in claim 7, characterised in that thespot or line weldings are provided at a temperature of 70 to 110° C. 9.A seed tape as claimed in claim 1, characterized 10 in that the fibresof each non-woven layer (3) are of a length of 5 to 9 cm.
 10. A seedtape as claimed in claim 1, characterised in that the biodegradable,gas-permeable, flexible, non-woven layer (3) is formed by a row ofpockets (3′) of non-woven polylactide (PLA) fastened to the carrierstrip (2’) at an equidistant distance, and where each pocket includes aseed.
 11. A seed tape as claimed in claim 1, characterised in 20 thatthe flexible non-woven PLA layer (3) is of a weight of 10 to 40 g/m².12. A seed tape as claimed in claim 11, and where the seeds are sugarbeet seeds, characterised in that each germinating unit (1 a, 1 b, 1 c)is delimited by a circumferential welded seam (26), which is locallyinterrupted in order to provide an opening (27) through which radiclesand seedlings can advance.
 13. A seed tape as claimed in claim 1,characterised in that that it contains paper-like pieces (21 a, 23, 27a) produced by placing cellulose fibres, SAP-crystals (8) and grains ofcarrier (7) and adjuvants (9) on the surface of a suction cylinder bymeans of air.
 14. A seed tape as claimed in claim 13, characterised inthat the adjuvants (9) are placed in a small capsule (22) in eachgerminating unit (1 a, 1 b, 1 c).
 15. A seed tape as claimed in,characterised in that the flexible non-woven PLA-layer (3) presents asuction capacity of 0 to 30 mm.
 16. A seed tape as claimed in claim 1,characterised in that the water-absorbing additive or additives (8),including SAP, and adjuvants (9) including pesticides, can be absorbedin or adhered to a blotting paper piece (27) provided with a plasticcoating, for a slow release of additive and/or adjuvant, said blottingpaper piece (27) being placed inside each germinating unit (1 a, 1 b, 1c) and resulting from a cutting off from a high speed-produced roll ofblotting paper at 500 m/min, where the above water-absorbing additive(8) and adjuvant (9), if any, are sucked into or glued onto saidblotting paper piece.
 17. A seed tape as claimed in claim 1, wherein thelayer (30 is locally interrupted a short distance along the seed tape,each germinating unit (1 a, 1 b, 1 c) includes an adjuvant (9), and eachseed tape is cut into separate germinating units prior to the irrigationand/or the bedding out.
 18. A seed tape according to claim 15 whereinthe suction capacity is 5 to 15 mm.